How to Check for a CPU or GPU Bottleneck
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Before you spend money to fix low FPS, you need to know what’s actually holding you back — your CPU or your GPU. This guide shows you how to diagnose a bottleneck in minutes using free monitoring, so you upgrade the right part.
Every system is “bottlenecked” by something — that’s normal. The goal is to know which part limits the games you play, then fix that one.
What a bottleneck really is
A bottleneck is simply the component that hits its limit first. If your GPU is at 99% and the CPU isn’t, the GPU limits you (good for gaming — you’re getting full use of the card). If your CPU pins a core at 100% while the GPU coasts, the CPU is the limiter.
Step 1 – Set up usage monitoring
Use MSI Afterburner with RivaTuner (RTSS) for an in-game overlay — see our MSI Afterburner guide. Enable these in the overlay:
- GPU usage (%)
- CPU usage (%) — overall and per-core if possible
- Framerate
- GPU and CPU temps (to rule out thermal throttling)
Step 2 – Play and read the numbers
Load into a real game (not a menu) and watch the overlay:
| What you see | Diagnosis |
|---|---|
| GPU ~97–100%, CPU lower | GPU-bound — normal; lower settings or upgrade GPU for more FPS |
| GPU well under 100%, one CPU core maxed | CPU-bound — upgrade CPU/RAM or lower CPU-heavy settings |
| Both low, FPS capped | A frame cap, V-Sync, or power limit is holding you back |
| Either component very hot | Thermal throttling — fix cooling first |
Step 3 – Confirm with a resolution test
A quick trick to confirm:
- Note your FPS at your normal resolution.
- Lower the resolution dramatically (e.g. to 720p) and retest.
- If FPS barely changes, you’re CPU-bound. If FPS jumps up, you were GPU-bound.
Step 4 – Act on the result
- GPU-bound and want more FPS: lower heavy settings, enable upscaling, or upgrade the GPU — see Best GPU for 1080p / 1440p.
- CPU-bound: enable XMP/EXPO, close background apps, disable VBS, or upgrade — see Best CPU for Gaming 2026.
- Capped/throttled: remove the frame cap or V-Sync, raise power limits, or fix cooling with an undervolt.
Don’t chase a “perfect” 0% bottleneck
It’s normal and healthy to be slightly CPU-bound at low resolution and GPU-bound at high resolution. Aim for the GPU near 100% in the games you care about at your real resolution — that means you’re using the hardware you paid for.
Related guides
- Best CPU for Gaming 2026
- Best GPU for 1440p Gaming
- MSI Afterburner Guide
- Testing PC Components Using Benchmarking Tools
Check for a bottleneck by watching GPU and CPU usage in an overlay and running a resolution test. Whichever component hits its limit first is the one to address — and now you know which, before spending a dollar.